Whether or not it applies, sherman act suits are not things that happen very often. Getting a state's attorney office interested is going to be a non-starter. If there was a pool in jurisdiction that actually got attention along these lines, I'm sure they'd just move overseas overnight.

If you really wanted to attack a pool I'd suggest a tax or employment authority. I consider it very unlikely most pools are conducting themselves appropriately in regards to accounting, withholding and employment law.